In general, an automatic washing machine is designed to remove contaminants from clothes, bedclothes, etc. (hereinafter referred to as “laundry”), using friction and the impact of water flow caused by the rotation of a pulsator or other member in a drum containing water and detergent.
In general, when washing or spin-drying is performed after the laundry is placed in the drum, the laundry may gather at one side of the drum causing an unbalanced state of laundry in the drum.
Fewer problems may occur if the laundry is spread around the drum evenly while the drum is being rotated during the washing operation. If the drum is unbalanced, however, vertical and horizontal vibrations may be generated in the drum. Such vibrations may increase in magnitude as the laundry in the drum becomes more unbalanced.
Vibrations caused by the unbalance of laundry in the drum may result in audible noise. Furthermore, the vibrations may cause the drum to collide with a tub surrounding the drum or a cabinet that encloses the tub and drum and forms the exterior of the washing machine. Such collisions and may cause damage to components within the washing machine.
To solve such problems, a suspension for attenuating and/or absorbing vibrations has been proposed.
Conventional suspensions are installed at a plurality of positions along the periphery of the drum to connect a lower peripheral surface of the drum to an upper portion of the cabinet. Each suspension incorporates a spring therein such that when the drum vibrates, the vibrations can be attenuated or absorbed by the springs.
To elaborate, a conventional suspension includes a main body having an open top and an open bottom; a snubber bar inserted into the main body through the open top such that the snubber bar may slide along the main body, connected to a lower surface of a top panel of the cabinet; a seal connected to an end of the snubber bar; and a spring surrounding the snubber bar and between an uppermost surface of the seal and an uppermost surface of the main body. When the drum vibrates, the elastic force of the spring allows the main body to slide along the snubber bar in a reciprocating manner so that the vibrations may be absorbed and/or reduced.
Further, the main body is fixed to a lower peripheral surface of the drum, and an orifice or opening that allows air to flow in and out of the main body is in a sidewall of the main body. The opening may be at a position higher than that of the seal when the spring is maximally compressed. In this configuration, if the seal is raised or lowered as the spring is compressed, the air between the seal and the top surface of the main body may flow out of the main body through the opening, and the outside air may flow into the main body through the opening. Accordingly, it may be possible to achieve an air damping effect that applies resistance to the movement of the seal.
An automatic washing machine that includes a conventional suspension may fail to achieve sufficient vibration damping when the weight of the laundry in the drum is small and/or in an unbalanced state in which the laundry is agglomerated at a side of the drum, for example at a left or right side and/or an upper or lower side, the spring within the suspension may be barely transformed by the vibration of the drum, resulting in a failure to achieve sufficient vibration damping. Furthermore, since the downward movement of the drum is small, the drum may vibrate vertically raising the risk that the drum may collide with the top plate of the cabinet.
Moreover, when the weight of the laundry in the drum is large and unbalanced, a compression amount of the spring within the suspension may increase and/or be excessive. As a result, vibrations may not be dampened effectively. Furthermore, as the seal is raised, the amount of the air that exists above the seal within the main body may decrease, resulting in a failure to achieve sufficient air damping effect.
Conventional suspensions may be disclosed in Korean Patent No. 10-0253221 (Registered on Jan. 22, 2000) and Korean Patent No. 10-0253222 (Registered on Jan. 22, 2000).